...One day in 1952, Lavrov was going home after the May Day civil parade when suddenly somebody called out to him. Turning round, he saw an old friend named Pavlov.
"Hallo," Pavlov said smiling. "Glad to see you. I don't think we've met since 1945."
Alexei was also pleased to see him. They talked of old times and their friends.
"By the way," Pavlov said. "Are you spending the evening with your family?"
"I'm afraid I haven't got a family yet," Lavrov answered, "and I haven't made up my mind yet where to go."
"Then come to my place at eight o'clock this evening", Pavlov said. Alexei was delighted, and at exactly eight he was knocking at Pavlov's door. He went into the room, and was introduced to the guests. Everybody was enjoying the party. Some of the guests were dancing, others were talking, laughing and joking, when somebody began to play the piano and sing a beautiful song. Everybody stopped talking at once. At that moment two more guests appeared. They were a young woman and a boy of about sixteen. As soon as they came into the room, they, too, stopped near the piano, listening to the singer. When Alexei looked at the woman, he thought that he had met her somewhere before, but he couldn't remember where it was... He no longer listened to the song. He looked at the woman, trying to remember where he had seen her. The boy called her "Mother", but she didn't look more than twenty-five. Alexei went up to Pavlov and asked him, "Don't you think that mother is too young for her son?" "Well, he is not really her son," Pavlov answered. "In 1943 an officer asked her to take a little boy from the front to Moscow and..."
Interrupting him Alexei cried out. "Of course, that's who it is..."
And that is the end of the story. Now you understand why there's a difference of twenty years between the Lavrovs' two sons, don't you?